Dividing head



Sept. 5, 1944. J. R. HANSENL 2,357,329

DIVIDING HEAD 7 INVENTOR JAMES l?. LM/vs f/v fJ. Rf HANSEN Sept. 5, 1944.

2 v//l/ o I ww? UN m 4 f` vom 1 ,f w m. 411 w 7 of ,w I M nl www wma M 7a. 4 4J www m 1 a M e wu Y 0 s MMM 35% i@ :LJ 7 rd MW 5 `W f N f A jy/ ,au ma 41, VII M nu m n Patented Sept. 5, 1944 James lR.,Hansen, Bremerton, Wash., assgnorof two-fifths to Gustav Drews, Garden City,

ApplicationlNovember 6, 19411, serial V1i0.4:1s,fo33

l2 Claims.

This invention relates in general to dividing heads for machine Shop tools, such as milling fis aimed to -providg'an improved 'dividing head Afor machine shop tools, such as r'nilling machines,

spiral milling machines, drill presses, 'and the like requiring no additional dividing plates, dinerential gears, or the like.

It is still 4another'object ofthe present invention to provide an improved dividing head characterized by having the indexing holes on 'the faces 'thereof arranged in aspira] instead 'offin a circle and by 'having a pin receiving device 'for cooperating with such spiral indexing holes.

It is still another object of the present invention to provide .an improved dividing head characterizedby having a reversible control disk provided With spiral rows of indexing yholes on both sides thereof constituting one of the main Vparts of the present invention and an equal number fof concentric circular rows of indexing holes on the reverse side of the disk to the spirals respectively. According to well known practice, the circle of holesv on either side of the disk may be used with a standard machine sho'pftool, 'such as a milling machine, drill press, or the like, to control the cutting operations.

These and other features, capabilities and adhead operatively associated with a work table;

Fig. 2 is a vfront elevation of the dividing head showing one facel of the control disk'drawn to a larger scale than that'shown in Fig. 1;

Fig. 3 is a side elevation partly in section on the line 3-3 lof Fig. 2 ofthe dividing head drawn to a scale larger than that shown in Fig. 2;

Fig. 4 is a section on the line '1lf4 of Fig. 2; Fig. 5 is a section on the line 5-5 of Fig. 2; Fig. 6 is a section on theline 6--6 of Fig. 2; and

Fig. 7 is a section on 'the line 1-1 of Fig. '2. In the embodiment shown, the shaft I is illustrated as journaled in Aa. housing 2 with a work support, here Vshown as `a work receiving table 3 secured to the upper end thereof. It is, of course, obvious that lthe shaft I 'is merely illustrative of the main shaft of a machine shop tool, whether rotatable about `a Vertical axis, a horizontal axis, or an'inclined'axis of anyma- `chine shop tool, such as -a milling machine, drill press, or the like. y Y

'The shaft I is operatively yassociated with the shaft 4 of the dividing head 5. The operative connection between the shaft I and shaft I4 in the present "instance ifs `vshown as including 'a worm 6 on the fshaft il `in 'mesh with a lWorin wheel 1 on the shaft 'i'. While not limited to a reduction of 40 to 1, since .the rotation of the driving shaft `I generally Vis f1 to 40y rotations of the .driving `shaft 4 in the -standardmachine shop tool, it willbe assumedfthat thefreduction here 't'oo "is illustrative 'of ith'e standard 40 to 1 ratio.

The shaft 4, in thepresent instance, is journaled in the 'bearing 8 'extending from 4the housing 2` and the 'sha'ft extends through 'and "beyond the bearing Ato recente the 4Vgear sleeve 9 in which the *shaftv 4 Vis freely rotatable. The lgear sleeve 9 'is typical Jof the 'floating sleeve ,provided in nearly "all :heads for spiral milling. VWhen a spiral milling operation Vis performed, the sleeve 9 with itsa'ssociated 'parts"is, according to standard practice, A'operatively connectedto ro- -tate With the horizontal table `screw of the milling machine. When a dividing or indexingoperation only is performed, the *sleeve 9 is ffixed to soine stationary part of the frameor housing 2 'such as the 'extension ID, the extension 4I'll in the `present instance being connect-ed by the screw I I 'to the'arm 'I 2 which has an enlargement 'I3 provided 'with 'an opening to 'receive the diminished portion V|11 -o'f the sleeve `iijvvhich enlargement I3 in turn is secured vor anchored to the shoulder portion I5 of the sleeve 9 by the pin I6.

`lso mounted on the diminished portion I4 I is the collar 1l which Ais ixed to travel with the sleeve 9 and 'the Y`arm I2 "by means of the screw I8. On the collar 11, thereis rotatablyV mounted enlargement t9 of the "arm 2Q. The arm 20, in turn,' is connected in the Yrst place to the arm I2, in the present instance by the' micrometer 2l, the stud v22 ofjthemicrometer 2l being pivotally connected by thelpin 23* to the outer end of the arm I2, and thegra-duated vcylindr'ic'al portion '2'4 being rotatably mounted'in the 'cap 25 provided VWith "a'vv ball* 'extension 26 'swiveled in theenl'argernent Eloi the farm 20. The arm 2ll,"in the second place, is connectedto Hthe dividing guide, hereshownjas ajplate or has a stud |34 formed to engage one of the reesses or holes 35 in the rear face of the disk 28. This pin 29 is in turn provided with a spring 36 tensioned between the shoulder 31 and the inner end of the housing 32, yieldable to urge the stud |34 outward. The bracket 33 is slidably mounted in the slot 34 of the arm 20 so that the stud |34 may either enter and register with one of the holes 35 in the outer circular row of holes 35 or in one of the lholes in the intermediate cirrow of holes 39, the bracket 33 being provided with a slot 40 to receive the head of the setY screw 4|, the stem 42 of which cooperates with the slot 43, the head 44 of the stem 42 being in turn secured to the arm 2li).

The dividing plate 28, as shown in dotted lines in Fig. 2, is provided with three concentric circular rows 35, 38 and 39 of holes on the rear face of the disk or plate. On the front face this disk is provided lwith a spiral row of holes 45. This disk 28, as clearly shown in Fig. 3, is rotatably mounted on the diminished portion |4k of the sleeve 9.

Each of the rows 35, 38 and 39 of holes in the present instance is provided with a different number of holes. Furthermore, the holes of each row are in circles concentric to one another.

In the present instance, the spiral, convolute or helical row of holes 45 consists of ve complete 360 turns. The holes of the ve turns are in turn in alignment with one another radially of the disk 28 and also in alignment with the holes of the row 38. Consequently each 360 turn of the spiral row 45 has 126 holes or recesses. From the foregoing it will thus be seen that the position of a hole in any one of the rows 35, 38, 39 and 45 and, consequently, of the disk' 28, may be angularly adjusted relative to the arm 29 according to the adjustment of the micrometer 2 I. In other words, since a hole in each of the turns in the spiral row 45 is disposed in a radial line relative to the disk 28, if the rear face of the disk 28 containing holes 35, 38 and 39 were used to .cooperate with the pin |34 to fix the plate 28 relative to the frame 2 through the extensionY |70, then since the arm and not the arm |2 is thus xed to the disk 28 by the stud |34, and the arm l2, and not the arm 20 is xed to the frame 2 by the screw extending into the extension I0,

Vthe position of the disk 28 may still be adjusted .relative to the frame 2 by the manipulation of diminished portion |4 of the sleeve 9 against the collar |1, there is provided a collar 49 which is secured to the diminished portion I4 by the screw v5|) andhas a shoulder 5| extending beyond the diminished portion |4 of the sleeve 9 andV engaging the outer or front face of the plate 28. 'The adjustable angle arms .52 and 53 are rotatably mountedrelative to the sleeve 49. In the present ,instance, the arm 52 has an enlargement 54'rotatably mounted on the collar 49 and the arm 53 is provided with the enlargement 55 rotatably mounted on the collar'56 which is .rotatably mounted on the collai` 49. The enlargement 55 is connected by the set screwv51 to the collar 56 and the collar 49 has a flange 58 engaging the outer face of the collar 56 which, in turn, engages the outer face of the enlargement 54 of the arm 52 so that the flange 58 in this way anchors both arms 52 and 53 on the collar 49. After the set screw 51 has been tightened to anchor the arm 53 at a predetermined angle relative to the arm 53, then the arm 52 may through the slot 59 be adjusted a greaterr or less degree relative to itsother position by means of the set screw 60 extending through the c ollar 56 and into engagement with the stop nut 6| in the slot 62 in the ,enlargement 54 of the arm 52. The arm 53 (see Fig. 2) is ,also provided with a slideway 63 to receive the marker slide 64. This marker slide (see Fig. 2) is provided so that the operator may position the marker 64 opposite the rpredetermined hole or turn in the spiral 45 in order to guide him in arriving at the stopping place when vactuating the crank handle 46. This is of value when more Athan one turn of the handle is required per division.

The pin housing 41, in the present instance, instead of being secured'to yan integral part of the crank arm 46, is mounted at the end of an arm 65'which is slidably adjustable in the enlargement 66. The position of the arm 65 in the enlargement 66 may be secured in position by the 'set screw 61. The enlargement 66 in turn has an extension 68 extending through the slide block 69, and connected to the slide block 69 by the screw 10. The slide block in turn is provided rwith a nut 1| to anchor the slide block 69 in position onV the slide 12. The slide 12 (see Fig. 2) has two slots 13 and 14, the slideblock 69 being slidably mounted in the slot 13 in the present Vset-up. One side'of the slide 12 is provided with positioning scales 15 and 16. The position of the slide block 69 relative to the scales 15 and 16 will be determinedby the pointer 11 (see Fig. 5,) secured to the slide block 69. 'Ifne degree of freedom of rotation of the enlargement 66 relative to the slide block 69 will be determined by the set screw 10.

The slide 12 isadjustably mounted on the arm v18 of the crank 46, such arm 18 having slideways 19 (see Fig. 4) on the rear side to receive the A bolt 8| extends from the slide 12 through the slot 82 in the arm 18 to receive the nut 83cm the front end thereof.

, rIhe slot 82 is provided to alford radial adjustment 'of the slide 12 relative to the disk 28. On the front face of the, arm 18 and adjustably mounted in the slideway 84 there is provided the support through which bolt 8| also extends so that the nut 83 may secure not only the slide 12, but also the support 85 in position. The upper end of the arm 85 is provided with a concave `seat86 toreceive thevpin housing 41 for the purpose hereinafter to be described. To facilitate proper radial positioning of the slide 12 relative to the disk 28, a'scale'81 V(see Figli) is formed on one side of the arm 18 and an indicator 88 formed on the slide 12 positioned adjacent to the scale 81.

The crank 46 is preferably secured in place on the front end of the shaft 4 by the screw 89.

When it is desired to reverse the disk 28, it is of course only necessary to remove the screw 89 thereby to remove the crank 46 and associated parts, and then'to remove the screw 59 which secures' the collar 49 to the sleeve I4 and at the same time anchors' the angle arms 52 and 53 in position to cooperate vwith the front face of the disk 28. Thereupon, after the' disk 28 has been crank 46 and associated `par-ts on the front end of the shaft 4 and replace the screw Y89. The -pin housing 44l (see Fig. 3), is provided wi-th a spring 9U for normalh7 urging the pin portion 48 outward, such spring 90 being positioned between the shoulder .9| of the pin 48 and the lshoulder 92 of the housing y4l. The pin -48 is provided with a shank 93 extending to and beyond the front end of the housing 41 there to receive the convtrol head 94. The housing 4-1 is also provided with two recesses, a long recess 95 and a short recess 85 to cooperate with the pin 91. When lthe pin 91 is positioned inthe recess 95 as shown, the pin 48 is rin extended position to enter an opening in the disk 28, whereas when the pin 91 vis positioned in the recess 96, then the pin 48 just clears the disk 28.

VIn place of the vdisk 28 having a plurality of spiral rows of holes 45 on one face and a plurality of circular rows of holes 35, -38 and 39, several disks having different arrangements of holes may be provided without departingl from the general spirit of the invention. As an instance, there may be provided a disk having one spiral row of holes on one face of one pitch and a certain number of holes per turn and another spiral row on the other face of the same pitch, but having a different number of holes per turn. A circle must cooperate with the spiral. When a number of disks having only one spiral and one circle on each side are used, these circles and spirals should be the same distance from the center on all of the plates or disks. This construction would enable the rest or'support 86 and the pin housing 32 to remain stationary. It has been calculated, as an instance, that with a set of three disks each having two spiral rows Yof holes and two circular rows of holes, one spiral row and one circular row on each face, each spiral havling ve turns and each spiral having a differentY number of holes, as an instance, 132, 126, 114, 11'1, 102 and 7-8 holes per turn, they would cover all :divisions from 2 to well over 400.

Whenv as in the last example the machine is equipped with three disks, each having a pair of spiral rows of holes, but di-ierent in number, the rst disk having on one face 132 holes per turn and on the other face 126 holes per turn, the second disk having on one face 114 holes per turn and 111 holes pei` turn on the other face, and the third disk having on one face 102 holes per turn and on the other face 78 holes per turn, then the disks can be arranged so that with each diiferent spiral in the triple spiraldisk a different adjustment of the support 85 may Vbe vmade by a rather simple expedient. As an instance, the support may be providedv with three holes, 98, 99 and llll, disposed one above the lother radially of the disk to register with an opening in the arm 'I8 in line with the hole 98, see Fig. 3, and then, after the Vrequired registration has been made, a pin 102 may be placed in the registering holes to X the position so selected. For certain purposes the hole l93 will register with the aforementioned opening in arm 18 when the 'first spiral is used. When the third spiral on the triple spiral plate is in use, hole in support 95 will register with the hole in arm 18.

The. idea of the spiral arrangement, namely, the use of the spiral rows of holes, is to make it possible to lose or gain a given number of holes in a given number of degrees of revolution of the handle 46. For example, with the arrangement illustrated lin Fig. 2, two holes are lost in one revolution. The arc |03 passes through the fourth hole on the second turn of the -spiral showing that the proportion of loss is constant. The eifect is the same, therefore, as with a standard plate having 124 holes instead of 126 holes, the number of holes per turn in the plate- 28. IWhen the arm 65 is operatively associated with the slot 14, instead of losing holes per turn, it is possible to grain holes per turn, it of course being assumed that the handle 4s will be turned clockwise vrelative to the disk 28 during the operation thereof. In Fig. 2, for instance, if the block 69 were located in the same relative position in the slot VF4 that it now occupies in the slot 13, each revolution of the crank handle 46 would intercept 128 holes instead of 124.

It should also be noted that the gain or loss of any given number of holes is not confined to complete or unit turns of the handle 4G. Requirements might make it necessary to lose two holes in one and one-half turns of the handle. The radius of the arm 65 then would have to be longer as measured on the scale rl5; If it had been one and two-thirds turns, the radius would have to be still longer. These fractional turns are limited only by the number of holes on the division circle 35. A marker |04 is provided to indicate fractional turns and the number of complete turns- When the marker.is reached by the pin-48 in its coursealong the spiral, the standard headlock is set to make sure the shaft 4 will not turn, and the pin housing Mis returned to its rest or support 39. The pin 91 is dropped in the half way hole 98. In this position, the pin 48 will just clear the plate 28. The pin E34 is then withdrawn and the plate turned until the rst hole on the spiral 45 is again opposite the tip of pin 48. The operation is then repeated. For some of the low numbers where more than oneturn of the handle is required per division, a marker slide iiiis provided for use by the operator if he so desires. The arm 52 has two positions as indicated. The angle 195 is ascertained and thereupon the stop nut 5l and the set screw 69 positioned wherein the angle |95 will correspond to the number of holes to be gained or lost per group. This feature is added so that the operator does not have to count the number of holes of correction at the end of each group.

Specific examples will now be given showing the use of a disk having a spiral row of holes 45 with 126 holes per turn. First we will describe an example where the result comes `out even and then one where the micrometer v2l is used to make a small correction. These correction factors are ordinarily so small that they could easily be ignored practically, but wh'ere extreme accuracy is necessary the micrometer 2| is used. It might also be stated that the` majority of problems have no correction factor.

However, to return to the example where the result comes out even: Let it be required to div ide the circle into 553 parts. Our base number will be 5040, that is, 126 times 40 equals 5040, taking into account the ratio of 40 to 1 of the shaft 4 to the shaft l. If the base number is 5040 and it is divided by the number 553,.the quotient will be 9 with a remainder of 63. In terms of holes, it will then be necessary to lose "63 holes in the 40 turns of the handle 46. Since it is desirable to lose as few holes per group within limits as possible, we will elect to lose 3 holes vand the result roughly will be groups.

per group in this case. That makes 2| groups. Furthermore, if the number of holes to be lost, 63, is subtracted from our base number 5040, our new corrected base number will be "4977 which is exactly divisible by the number to be divided, 553. If this new corrected base number "4977 is then divided by the number of groups, to wit, 21, the number of holes in each group is found to be "237. The group marker |04 will now be set at the 237th hole on the spiral (see Fig. 2). That is, dividing 237 by 126, the number of holes per turn will call for one com- Aplete turn of the handle and afurther turn until the 111th hole in the next turn of the spiral will have been reached. The marker |04 as aforesaid (see Fig. 2) has been placed on this 237th hole of the spiral or the 111th hole of the second turn of the spiral 45. The angle |05 is set for three holes and the angle |06 is, on the other hand, set for 9 holes. The angle |06 of 9 holes is used for all divisions except where the marker is included in the angle and a return to the starting hole has to be made in which case the arm 52 is pushed back against the stop |07 to include 12 holes. This latter operation occurs 20 times in this case where there are twenty-one groups.

The next example to be explained calls for a small correction. As an instance, where it is required to divide the circle into 383 parts. In such case there will be a remainder, a small fractional part of one hole which must be compensated by the micrometer 2 The original base number "5040 will again be divided by the new number "383 giving a quotient of 13 With a remainder of 61. The corrected denominator then will be 4979 which contains the new number to be divided, 383, exactly thirteen times. The remainder "61 in terms of holes must, however, be lost. This time four holes will be lost to the group in which case divide the remainder "61 by 4, Now take the new base number 4979, multiply it by 4 and divide by "61 and the result will be 3263%1. The marker |04 will now be set at the 326th hole on the spiral. The total error to be taken care of by the micrometer 2| is determined by -a simple proportion. The answer flowing from this proportion also indicates whether the micrometer 2| tis to be closed or opened to make this correction. The proportion is in which will equal 504030/326, that is, 504015463. The handle 46 will, therefore, have turned 15/163 of a hole too far. The correction must be made by turning the plate 28 that much to the left. This is done by closing the micrometer 2|. The distance between the holes at the radius of the micrometer is 0.259 inch. The 0.259 inch is obtained 4as follows and it represents the distance between the holes at the radius of the micrometer, in this case the radius is 5% inches, as can be seen by scaling the drawing. The diameter will equal 103/8 inches, 10.375 inches. Multiply by pi or 3.1416 to obtain the circumference, that is, 3215941000. The circumference of the circle described or traveled by the micrometer is thus 32.594 inches. There are 126 sectors or holes. Therefore, the distance between ,these sector points at the radius of the micrometer is found by dividing 32.594 by 126, obtaining 0.2586 or 0.259. This distance 0.259 is measured on the circle instead of by a straight line between sector points, but the difference would be infinitely small.

The error is equal to'lg of a hole or sector,

but the sector measures 0.259 inch. Therefore, to convert the error, expressed as a fractional part of Vthe distance between two points, into terms of inches, it is necessary to multiply the one by the other, that is 1%63 by 0.259, equalling 0.0238 or 0.024. This distance 0.024 is measured on the micrometer in the usual way.

It is obvious that if this distance were measured on a smaller portion of the wedge or sector that is, nearer the center of the disk, that this error expressed in terms of tooo of an inch on the micrometer would be much smaller. The point is that, if the size of the disk were reduced, the micrometer would also be nearer the center of the disk and, hence, the reading 0.024 inch could not be produced, but a much smaller reading, proportionate to the radial distances, would be produced.y

This 0.024 inch loss can be spread as the operator desires, or for nearly all practical purposes can be ignored. The angle |06 will now be set for 13 holes and the angle |05 for 4 holes, in which case the number 13 is determined from the quotient when the number "383 is divided into 5040 and the number "4 is determined by the number of holes lost.

To further show the flexibility of this device, the number "383 of the last example will again be used as the divider, in this case for losing three holes of the group instead of four holes. Here the new base number 4979 will be multiplied by "3 and divided by 61 to equal 2445?/61. The marker |04 will now be placed at the 245th hole on the spiral, that is, one complete turn of 126 holes and 119 additional holes of the second turn. -Our proportion then will be in -which case x will equal 5039237/245. Then, if this new number 5039237/245 is subtracted from 5040, the result will be V245, and in the terms of holes will equal a total error 0f 8/245 of a hole. Now, multiplying *7245 by 0.259 inch, the yanswer will be 0.008 inch, the total correction on the micrometer for the entire 383 divisions. The micrometer will now be opened because the value of :r is under 5040. In other words, the ratio is 40 to 1, so there are 5040 holes passed by the handle for every turn of the worm gear and the job, i.y e., 126 40=5040. But the error is equal to 8/45 of the distance between two of these holes. In other words, the error in terms of revolution of the job is reduced 40 to 1 in terms of revolution of the handle. Stated another way, it would be clear that, if the error was one hole on the dial, then that error would be j/5040 of one revolution inasmuch as it takes 5040 holes to make a. revolution of the job.

kBut the error is not one hole. It is a very small fractional part of one hole, namely, 8/245 of one hole. Therefore, the error stated in terms of revolutions of the job, must be proportionately smaller. The correct fractional equivalent is found by multiplying the two fractions together, namely 8/245 multiplied by V504@ equals 1/154350. Translated into terms of revolution ofthe job, the error to be corrected is equal to 1/154350 of one revolution.

vWith reference to the stop |01 and the method of adjusting angle |05 of Fig. 3, the pin, not Visible from the outside, is pressed into collar 56 and operates in the slot in the enlargement of arm 52, said enlargement being designated v54. The angle |05 isnow set for three holes and the angle |06 for thirteen holes.

` by 128; the resultwill be 39 with a remainder of 48. It is, of course, vobvious that the 48 holes could be taken ycare of on the lose side.v by setting the angle |6f for thirty-nine holes. If, however, as aforesaid 'we'solve the problem by Working it` on the gain side, then 128 times "40 equals 5120 which will be the corrected denominator on the'gain sideV and consequently subtracting 5040 from 512.0 eighty holes will be gained. If we allow two holes to be gained per group, it will call for forty groups in which case the corrected denominator "5120 divided by 40; will equal' 128. Now the marker |04 will be set atv the 128th hole, and the slide block 69 will be transferred to the slot 14 positioning the arm 65 to scale reading from a prepared chart to gain two holes in each group of 128 holes on the spiral. In this case, the pin 48 will drop back to the starting point and the plate will not have to be moved. Sincethere are 126 holes per turn of the spiral, 126 plus the two holes gained will equal 128 holes. Consequently'the angle |05 will be set for two holes.A In this case there will be forty holes for each division eX- cept where the marker is included in the angle between the arms 52 and 53, the pin'returning to the starting hole adds two holes so that these must be subtracted from the standard angle. Consequently, the angle |06 will nowA beset to include 38v holes.

On the losing side, that is when the slide 'block 69 is located in thel slot '|3, the standard angle is theA angle |06 and the angle |05 is the correction angle which is to be added. When'the slide block 69, however, is mounted in the slot 14, that is on the gain-side, the standard angle includes b-oth the angles |05 and |06 and the corrected angle is subtracted. Y

It is conceivable that the -disk 28 shown in Fig. 2 with the three circular rows of holes 35, 38 and 39 while concentric may each'have a different number so that these circular rows of holes on the front and the rear face of the disk with Y the circular rows of holes may be used as the ordinary dividing head plate having circular concentric rows of' pin holes. In order to facilitate positioning pinv |34 -so that it may cooperate with one or another of the rows of holes 35, 38 and 30, as shown in Fig. 3, the set screw 4| is manipulated to free the slide 33 in turn to position the pin |34 to register with one or another of the rows of holes 35, 38 or 39.

The marker |04 above referred to, as shown in' Fig. '7, consists of a stem ||1 having a head |08, the stem |1 being conformed to fit snugly in any one of the holes of the spiral rows 45. The marker may either be inserted in the final hole of the group or in the hole of the next turn so that its pointed end |09 will point toward and indicate the final hole of the series.

It is obvious that various changes and modifications may be made to the details of construction without departing from the general spirit of the invention set forth in the appended claims.

I claim:

1. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated with the main shaft of the machine shop tool, a dividing disk rotatably mounted on said control shaft, a handle fixed to said control shaft, a device locking said disk against movement with said control shaft, said disk having a spiral row of pin receiving openings, a pin holder operatively associated with said handle, and a pin -operatively mounted in said holder toenter any one of the openings in said spiral row of pin receiving openings.

2'. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated with the main shaft of the machine shop tool, a dividing disk rotatably mounted on said control shaft, a handle fixed to said control shaft, a device locking said disk against movement with said control shaft, said disk having a spiral row of pin receiving openings, a slide support mounted; on andextendingr transversely of said handle, an arm operatively mounted on said: support to assume a predetermined ang-le withr said support, a pin holder secured to the end' of said arm, and apin operatively mounted on said holder to enter any one of the openings in said spiral row of pin receiving openings.

3. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated with the main shaft of the machine shop'tool, a dividing disk rotatably mounted on said control shaft, a devicel locking said disk against movement with said control shaft, said disk having a spiral row of pin receiving openings, a handle mounted*` on said control shaft, a pin holder operatively associated with said handle, a pin operatively'mounted in said holder to enter any one of said openings, two angle forming arms adjustable to form various angles with one another to space off predetermined groups of openings in said disk, said angle forming arms being mounted on said control shaft, means for locking said handle to said control shaft, and other means for anchoring said angle forming arms and disk on said control shaft.

L1. In a dividing head fora machine shop tool, the combination of a control shaft operatively associatedwith the main shaft ofl the machine shop tool, a dividingdisk` rotatably mounted on said control shaft, a handle xed to said control shaft, a device locking said disk lagainst movement with-said control shaft, said disky having a spiral row of pin receiving openings, a slide support extending transversely of, and fixed to, said handle and having a slideway to either side of said handle, an arm adjustably mounted in either of said slideways to. assume a. predetermined angle with said support, a pin holder secured to the endr of said arm, and a pin operatively mounted in .said holder to enter any one of said openings.

5. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated with. the main shaft of the machine shop tool, a dividing disk rotatably mounted on said control shaft, a handle iiXed to said control shaft, a device locking'said disk against movement with saidcontrol shaft, said disk having, a spiral row of pin receiving openings, a slide support extending transversely of, and fixed to, said handle and having a slideway to either side of shaft, a device locking said disk against movement with said control shaft, said disk having a spiral row of pin receiving openings, a slide sulpport extending transversely of, and fixed to, said handle and having a slideway to either side of said handle, an arm adjustably mounted .in either of said slideways to assume a predetermined angle with said support, a pin holder secured to the end of said arm, a pin slidably mounted in said holder, a spring for urging `said pin upward into one of said openings when in registration therewith, and means for anchoring said pin against the tension of said spring to maintain it clear of said disk.

7. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated with the main shaft of the machine shop tool, a dividing disk rotatably mounted on said control shaft, a device locking said disk against movement with said control shaft, said disk having a spiral row of pin receiving openings, a handle mounted on said control shaft, a pin holder operatively associated with said handle, a pin operatively mounted in said holder to enter any one of said openings, two angle forming arms adjustable to forml various angles with one another to space off predetermined groups of openings in said disk, said angle forming arms being mounted on said control shaft, means for locking said handle to said control shaft, means for anchoring said angle forming arms and disk on said control shaft and a device for anchoring said disk against movement with said control shaft.

8. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated with the main shaft of the machine shop tool, a dividing disk rotatably mounted on said control shaft, a handle fixed to said control shaft, a device locking said disk against movement with said control shaft, said disk having a spiral row of lpin receiving openings, a slide support extending transversely of, and fixed to, said handle and having a slideway to either side of said handle, an arm adjustably mounted' in either of said slideways to assume a predetermined angle with said support, a pin holder secured to the end of said arm, a pin operatively mounted in said holder to enter any one of said openings and a device for anchoring said disk against movement with said control shaft.

9. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated With the main shaft of the malchine shop tool, a handle fixed to said control shaft, a dividing disk rotatably mounted on said control shaft and havingv a spiral row of pin receiving openings, a pin holder operatively associated with said handle, a pin operatively mounted in said holder to enter one of said openings, an arm rotatably mounted on said control shaft, means for anchoring said arm against movement with said control shaft, a second arm rotatably mounted on said control shaft, a connection between the free ends of said arms including a micrometer screw for effecting an adjustment, and a device for anchoring said second arm to said disk.- Y

10. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated with the main shaft of the machine shop tool, a handle fixed to said control shaft, a dividing disk rotatably mounted'on said control shaft and having a spiral row of pin receiving openings, a pin holder operatively associated with said handle, a pin operatively mounted in said holder to enter one of said openings, an arm rotatably mounted on said control shaft, means for anchoring said arm against movement with said control shaft, a second arm rotatably mounted on said vcontrol shaft, a connection between the free ends of said arms including a micrometer screw for effecting an adjustment, a second pin holder on said second arm, a second spin slidably mounted in said second pin holder, there being a row of pin receiving openings in the rear of said disk, and a spring for urging said second pin into one of said latter openings to anchor said second arm to said disk.

l1. In a dividing head for a machine shop tool, the |combination of a control shaft operatively associated 'with the main shaft of the machine shop tool, a dividing disk rotatably mounted on said control shaft, a handle fixed to said control shaft, a device locking said disk against movement with said control shaft, said disk having a spiral row of |pin receiving openings, a pin holder operatively associated with said handle, a pin operatively mounted in said holder to enter any one of the openings in said spiral row of pin receiving openings, and a marker secured to said disk to indicatethe last of a group of openings constituting a division.

12. In a dividing head for a machine shop tool, the combination of a control shaft operatively associated with the main shaft of the machine shop tool, a dividing disk rotatably mounted on said control shaft, a handle fixed to said control shaft, a device locking said disk against movement with said control shaft, said disk having a spiral row of pin receiving openings, a pin holder operatively associated with said handle, a pin operatively mounted in said holder to enter any one of the openings in said spiral row of pin receiving openings, and a marker having a pin formed to be positioned in one of the pin receiving openings in said disk to designate the last of a group of openings constituting a division.

JAMES R. HANSEN. 

